<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        // 对象的解构也可以指定默认值。

        var {
            x = 3
        } = {};
        x // 3

        var {
            x,
            y = 5
        } = {
            x: 1
        };
        x // 1
        y // 5

        var {
            x: y = 3
        } = {};
        y // 3

        var {
            x: y = 3
        } = {
            x: 5
        };
        y // 5

        var {
            message: msg = 'Something went wrong'
        } = {};
        msg // "Something went wrong"

    </script>
</body>

</html>